Fibrous substrates, such as polyamide carpeting, upholstery fabric, wool and other textiles, are subject to staining by a variety of agents, e.g., foods and beverages. Acid dyes present in such agents are especially troublesome staining agents, e.g., FD&C Red Dye No. 40, commonly found in soft drink preparations. Another common staining problem is caused by coffee. Prior proposals for inhibiting staining of polyamide substrates by acid dyes or coffee include application of sulfonated phenol-formaldehyde condensates, alone or in combination with hydrolyzed maleic anhydride polymers or polymers of methacrylic acid, acrylic acid, or itaconic acid, or combinations of the same.
U.S. Pat. Nos. 5,707,708 and 5,834,088 of Pechhold disclose the usefulness of 1-alkene/maleic anhydride copolymers having between about 0.4 and 1.3 polymer units derived from the 1-alkene per unit derived from maleic anhydride, the 1-alkene content of said copolymer comprising between (a) 100 and 80 mol % of an 1-alkene containing 4 to 12 carbon atoms and (b) 0 to 20 mol% of at least one 1-alkene containing 3 or 14 to 24 carbon atoms.
In an unrelated field of study, JP 62112608 discloses the use of styrene/maleic anhydride copolymers modified by reaction with p-aminosalicylic acid and triethylamine for coating the dentine surfaces of teeth. It does not disclose or suggest the use of such compositions for stain resistance on textiles or other fibrous substrates.
There is a need for improved methods of providing stain resistance to fibrous substrates, in particular for acid dye and coffee stains. The present invention provides such a method.